The U.S. government fails to properly vet people with access to secure areas at airports and harbors and those cleared to transport hazardous materials, according to a federal investigation launched by a Democrat who sits on the House Committee on Homeland Security.

News of this inconceivable homeland security vulnerability could not have come at a worse time, in the midst of heightened al-Qaeda activity that’s forced authorities to shut down a number of western embassies in the Middle East and Africa. It’s as if we’ve learned nothing from the 9/11 terrorist attacks.

In fact, the agency at the center of the probe—the Transportation Security Administration (TSA)—was created by Congress precisely to avoid a repeat of 9/11. Its duties are to protect the nation’s transportation system, mainly aviation. But the 56,000-employee TSA is also responsible for assuring that airport and seaport employees who access secure areas don’t have links to terrorism or other criminal offenses. The agency must also confirm immigration status.

This is done through the TSA’s Adjudication Center which employs contractors to help screen airline workers. Since 2003 the agency has conducted and/or overseen around 15 million background checks to reduce the probability of a terrorist or criminal attack on the nation’s transportation systems. This includes 450 airports and more than 350 seaports.

Relying on contractors to adjudicate security threat assessments poses risks, according to the new federal audit, which reveals that the center’s “timeliness and accuracy measures did not capture key data.” That sounds like diplomatic lingo for it cleared and credentialed job applicants who compromised national security.

In fact, investigators point out in their report that nearly two years ago a special working group already determined that “an excessive risk exists by allowing contractors to make security threat assessment approvals without sufficient federal oversight.” The TSA, which is part of the Department of Homeland Security (DHS), is still completing a “review” and “updating” a plan to improve the system, this latest report says.

In the meantime the country must continue to live with huge gaps in national security, hoping for the best because this multi-billion-dollar agency can’t get its act together more than a decade after the worst terrorist attack on U.S. soil. Just a few days ago, a separate government report blasted the TSA for a different but equally severe issue, rampant employee misconduct.

Federal officers at the agency commit an outrageous number of security breaches, the audit revealed, including naps during work hours. From 2010 to 2012 TSA officers were cited for more than 9,600 cases of misconduct, according to the probe. In nearly 2,000 cases officers were sleeping on the job, not following procedures or letting relatives and friends bypass security checkpoints. Thousands of others failed to show up for work, appeared late or left their post without permission.

The TSA has been rocked by a number of other scandals over the years. Last summer, for instance, a congressional investigaiton revealed that the agency is so inept the country remains inexcusably vulnerable to a repeat of 9/11. That’s because, according to that probe, the TSA fails in one of its key missions; to properly vet foreign flight students before they can take lessons or get a pilot’s license in the U.S. Remember that Islamic terrorists trained as pilots at U.S. aviation schools before using passenger jets as weapons of mass destruction.

Prior to that the TSA has been under fire for regularly missing guns and bombs during random tests at major U.S. airports and failing to meet federal standards by not screening cargo and passengers on hundreds of planes. A few years the House Transportation Committee called for an overhaul of the TSA, saying that the bloated agency has failed miserably to fulfill its mission. The TSA has “grown into an enormous, inflexible and distracted bureaucracy” that has lost its focus on transportation security, according to the committee, which also found that the TSA “lacks administrative competency” and “suffers from bureaucratic morass and mismanagement.”

In another zinger last year, the former head of the TSA called the agency a national embarrassment that’s hopelessly bureaucratic and disconnected from the people it is meant to protect. In a newspaper article promoting his new book about the agency’s inner workings, former TSA had Kip Hawley assures that “airport security in America is broken” yet it has transformed air travel into an “unending nightmare for U.S. passengers and visitors from overseas.”